1. Field of the Invention
The invention takes as its starting point a method of testing a control system.
2. Discussion of Background
With the preamble of patent claim 1, the invention refers to a prior art as is disclosed by Andreas Danuser and Hannes Ruscher in Was geschieht wann wo im Programm? [What happens when and where in the program], Technische Rundschau 35/1990, pp. 48-57. In the latter, a description is given of an observation tool which inserts instructions of the form:
MOVE (TAG, ADDR)
into the program to be tested, for example at the start and end of routines to be tested in the program, as a marker in the source text. In this case, TAG means a number which is allocated uniquely to the point in the program, and ADDR means an address at which a connecting point is addressed. When a marker inserted in this way is reached during the running of the source program, the instruction MOVE sends the TAG via the connection to the observation tool. In addition to the TAG, it is also possible for variable values to be transmitted. In the observation tool, a connection point receives the TAG, registers its arrival time and stores this information in an event list. The evaluation of the event list makes it possible to determine how much time is needed for which program section or how often a program section is executed. Statistics about the program flow can be compiled. If it is desired to observe a plurality of parallel computers simultaneously, a plurality of connection points are used, synchronized in time.
However, this observation tool does not register any external events; it records only points in the program, possibly with variable values, which are executed in the computers.
An observation tool of this type is described in more detail in EP 0 368 190 A1.